SVGs seem to be supported

[rzhao271]

Testing #241777

I get a warning with GPT-4o that SVGs aren't supported, but when I ask questions about it, the model answers.
For reference, I am testing with SVGs such as vscode-docs\docs\editor\images\intellisense\Enum_16x.svg.

[justschen]

we're not actually sending the SVG so it could be hallucinating. SVGs shouldn't be supported since it can be unsafe